Cultivar Maturity As An Avoidance Strategy for Asian Soybean Rust In the Mid-Atlantic.

Since 2004, Asian soybean rust (Phakopsora pachyrhizi) spores have been detected only once in Maryland.  And, this detection was during late October 2008; after the crop was considered no longer susceptible to damage.  Since spores will not overwinter in the region, it is likely that they will arrive late in the season with the exception of a mid-summer hurricane picking up spores in the south and depositing them upon Mid-Atlantic States.  This potential for a late summer arrival generated interest in using earlier than generally grown cultivars as a disease avoidance strategy.  Agronomic performance of MG 2 – MG 5 cultivars was evaluated under both full season and double crop production systems during 2005-2007.  Selection of cultivars in the MG 3 to MG 3.5 range was determined to likely support disease escape if the rust infestation occurred during the latter half of summer.